AN APPRAISAL OF EMPIRICAL MODELING AND PROPRIETARY SOFTWARE DATABASES FOR PERFORMANCE PREDICTION OF MACHINING OPERATIONS

Abstract

In this paper the importance of quantitatively reliable technological machining performance measures and their influence on the economic performance of machining operations has been demonstrated. It has been shown that since F.W. Taylor's time these technological performance measures were required to select cutting conditions which optimise the economic performance of machining operations and that the trend to use ‘recommended’ rather than economic ‘optimal’ cutting conditions can result in significant economic penalties which need to be eliminated. The ‘empirical’ approach and equations developed since Taylor's seminal paper are reviewed as are some computerised technological machining performance databases incorporated in modem proprietary software packages. The various strategies used to minimise the amount of testing required to establish the comprehensive sets of ‘empirical’ equations in manuals and handbooks published in the U.S.A., China and Russia are described and the penalties in the quantitative reliability of the predictions discussed. Two computerised machining performance databases are explored, the ‘short cuts’ identified and the plausibility of the predictions discussed. While the mathematical form of the ‘empirical’ equations in those databases could be considered plausible the values of the exponents and constants in the equations, which greatly affect the quantitative reliability of the performance predictions, can be considered dubious for the drilling databases. It is shown that a ‘large gap’ exists between the development of reliable technological machining performance databases and the selection of cutting conditions which optimize the economic performance of machining operations advocated by Taylor since 1907.